Kryolab
is the cryogenic facility of Lund University, located
at the Department of Physics. The purpose of Kryolab is to supply the university
with liquid helium and liquid nitrogen. These liquid gases are used for cooling
purpose in different kinds of research around the university and elsewhere.
Liquid nitrogen has a boiling temperature of 195.8 C (77K), while liquid
helium has a boiling temperature of  267.9
C (4.2K), which makes it the coldest known substance
on the planet earth. Helium is a natural resource, and - like mineral oil
- will not last forever. It is expensive and the use of it is dependent of
an unstable world market situation. Liquid nitrogen is the low-budget alternative
for many cooling applications, since it can be
easilyextracted from air.

From
the outside, Kryolab is open Monday to Friday, 08:00 to 16:00. From within
the building Kryolab is always open.

liquid
nitrogen

The
Sulzer LINIT 25 from 1988 produces around 90000 liter liquid nitrogen per
year, which is at the limit of the machines capacity.

Liquid
nitrogen (LIN) is available for anybody to take them self. You enter your
'user-code' and how many liters you have taken, at the terminal by the liquefier.
If you are a new customer, the Kryolab staff will help you to register and
get your own 'user-code'.

liquid
helium

Liquid
helium (LHe) is produced with a Sulzer TCF-20 from 1985 - rebuilt in 1995
- and is nowadays run mainly on recycled gas.

It has a built in auto-purifier which use the coldness of the system to "freeze
out" any impurities in the incoming helium gas. As much as 10 % air in
the gas can be purified in this way, but less impurities is always better.
Any kind of impurities entering into the turbine area of the liqufier will
definitely cause problems and blockages.

Liquid
helium will be filled in custom owned transport dewar by Kryolab staff.

The
typical LHe would come from a well in Texas, USA, where it is liquefied on
the spot. From then on, it will be transported in isolated containers, first
to the east coast and then with boat to a port in Belgium. A truck will carry
this container to some gas company in Sweden or Denmark. Here it will be transferred
over to minor dewars - like kryolabs 500 liters dewar, which is then transported
on a truck to Lund.

environmental
information

Since
helium is a natural resource in limited supply, kryolab and the users of liquid
helium have the aim to recycle as much as possible of the used helium gas.
The cryostats are closed systems where most of the boiled-off helium gas is
collected and sent back in hose to kryolab, where it is stored in high pressure
gas bottles. Later on, this gas will again be purified and liquefied. However,
helium consists of very small molecules which will leak and cause losses in
any system, and there are still some users who are not recycling helium gas,
so in reality around 60 % of the delivered liquid helium comes back as gas
to kryolab.